Rotary engine.



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996,199. ROTARY ENGINE. JOHN l-lnamza'r VAN DevsN'rna, Buffalo, N. 1'. Filed July 29, 1910. Serial No. 574,576.{

To all whom it may concern: i

Be it known that I Jolm IIsansa'r VAN Dsvsn'rsa, a citizen of the United States of America, residing at Buffalo in the county of Erie and State of New ork, have invented certain new and useful Improvements in Rotary Engines of which the following is a full, clear, and exact description.

' My invention relates to rotary engines having one or more pairs of rotors and more particularly to rotary engines with rotors each having a plurality of spirally dijposed and intermeshing blades.

mong the objects of my invention are, to provide a rotary motor which is very compact of very cw parts, and of comparatively high power for its size; also one which shall be smooth running and provide a uniform s eed and torque. Moreover the.

blades on tie rotors of my engine are of such a number and disposed at such an.

angle to the axis of the same, that the cross;

section of each presents a true spur geani thus securing transmission of rotation andf power from one rotor to the other and obviating the necessity of employing a pair; of auxiliary gears. These and many otheri advantages, which will be apparent to those skilled in the art, have been accomplishcdi ientirely if desired.

by the device herein shown and (ltHClllXtLl In the specification and the appended 1' claims the term fluid will be used but obvionsly my engine is a )plieable to be driven g with either compresset air or steam as well as any fluid under pressure. 1

Reference is to be had to the accompanying drawings which form part of this specification.

In the drawings like characters of refer. ence indicate like parts in the differentviews of which:

Figure 1 is a sectional elevation of the. casin in the preferred form of m engine and owe the rotors partly in see ion and partly in elevation. Fig. 9 is a sectional elevation taken on line A-R of Fi 1. Fig. l .l is a vertical sectional view the inlet. ort and the throttle and is taken on line ()l) of Fig. 1. Fi 4 is a horizontal sectional view of the inFct port and the throttle and is taken on line ll-F of Fig. 8. Fig. 5 is r a diagrammatieal view showing a pair of rotors with fluid inlet at each end, thus making the engine reversible. Fi 0 is a dia 'rammatical sectional end view taken on ice Gll of Fig. 5. Fig. 7 is a diagrammatical view of a modified form of rotors arranged to have the fluid inlet at the middle instead of at the end. Fi 8 is a diagrammatical sectional view ta (en on the line I-. l of Fig. 7. Fig. 9 is a diagrammatical view 0f.two pairs of rotors coupled on the same shafts with the fluid inlet at the outer end of each and the exhaust between the inner ends of each palr, thus balancing the end thrust. F1g. 10 is a diagrammatieal view of two pairs of rotors arranged to give a two-stage or tandem effect. Fig. 11 is a diagrammatical view of a single unit comprism r three pairs of rotors of different sizes an havin .one shaft. in common thus producing a lHCO- stage effect.

In the drawings en inc casin wine is provided with suitab e feet or arin surfaces 36. 13 is the 1 front head and 14 t is rear head. 15 are the rotors and the casin 12 preferably surrounds the rotors, as s town in Fig. 2, at. all points but where the rotors mesh and that. )ortion of the rear side of the casing which is between the planes of the axes of the rotors, where a screw-threaded aperture 16 is provided through which the exhaust from the engine may be carried off. While the casings closely fit the rotors and surround them as above stated, all that is necessary for the successful operation of the engine IS that t the fluid be confined between the blades until each has finished its cycle. All that is re 1 (aired for this is a narrow rib similar to i tlult shown in Fig. 8 at 75 and obviously the Figs. 1 to 4, 12 is the case surrounding the rotors may be omitted The front. head is provided with bearings 17 and 18 and the rear thead with bearings 19 and 20 each of \\'llt(l1 is provided with an anti-friction metal bushiing .21 and an oil reservoir 22. Rotatubly tmounted in the bearings 17 and 19 is the upper rotor shaft 23 and in a like manner .the lower rotor shaft 24 is rotatably mounted tin bearings 18 and 20. Each of the said .hearings is provided with an oil ring or chain 25 which dips into the oil contained in the oil reservoir 22 and constantly supplies these bearings with the proper amount of oil. The outer end of each of the :earings l9 and 20 is internally screw-threa ed and into the screw-thread in bearing 19, fits a thrust plug 29. This plug is provided with a central aperture which fits over a reduced peripheral diameter on the. shaft .23 and bet tween the inner face of the plug 29 and the shoulder 27 on the. shaft 221, is disposed a thrust bearing 28.

)earings 17 and 18 are. closed by means of Mounted upon each of the. 'lhesc rotors the plates 8."). shafts 23 and 24 is a rotor 15.

axis of the rotor and they are preferably formed by milling grooves in the periphery of the rotors in' much the same manner as l the cutting of a spur These blades may be of the standard gearmay be easily replaced by one with a dif- 5 ferent width aperture, hence the engine may i be readily ada ted for any pressure.

These blades make an acute angle with the? car. As shown ini Fig. 2 a cross section 0 each rotor presents i a per ect spur gear and the rule govermn the number of teeth in a spur gear would;

apply for the number of blades or teeth on i t the rotors; for instance, the rotors should never have less than twelve teeth each.

tooth shape or any other suitable section but the preferred form is shown in Fig. 2. In this figure it will be seen that the faces and 1' the top of each tooth form substantially a 3 semi-circle; the flanks of each tooth are formed. in substantially the arcs of a circle so that the two flanks of adjoining teeth form substantiallya semi-circle; arid also the sides of each tooth at the pitch line. where its faces and flanks join. for a distance not greater than one-quarter its full height. are substantially straight. This form oftooth will more ctl'ectuallv seal the blade against leakage of the fluid under pressure and thus make the engine more eflieicnt in operation. 38 is the admission ort and 3t! the admission port casing which is preferably integral with the front head 13 and provided at its outer end with an interior: screw-thread to which may be attached the fluid su ply ipe. A groove 40, greater in width t an tie diameter of the admission port 88, is made in the head 18 from the inner face thereof and this groove extends past the inner end of the admission port 1%.

h'lidably disposed within the groove 40 is a slide H by means of which the amount of fluid passing through the portmay he regulated. The slide 41 has attached thereto a rod 42 which passes up through a stufling box gland lit and may be operated manually but prcfcrably automatically in any of the j many ways well known to those skilled n the art. thus providing a governor for the speed of the cngmc. A porbholc )llltt. 44 l.'-'

set in flash with the inner face oft 1c head 13 and it is in sliding contact with the slide 41. Through the port-hole plate is a V-shaped aperture 4:) the sides of the V being curved I ctpuil to the radius of the rotors and the" wulth substantially ct ual to the height of l the blade or less, accort ing to the pressure of the fluid. Thus the pressure of the fluid is made to hear at the most effectual point and as this port-hole plate is a separate part, it

Obvionslv t 1e engine may be constructed with a flui inlet at both ends of the rotors and thus make the en ine reversible. This is clearly shown in a (iagrammatical manner in Figs. 5 and 6 where 46 and 4.7 represent the rotors, and 48 and 49, their respective shafts. 50 and 51 represent the inlets for the fluid pressure, thus when the fluid is being forced through the inlet tiO the rotors will revolve in the direction indicated by the arrows 52 but when the fluid is forced through the inlet 51, the direction of rotation will be as indicated by the arrows 53.

In Fi 7 and 8 I have shown a. modified form 0 my invention where a right hand spiral rotor 54 and a left hand spiral rotor 55 are mounted upon the same shaft and have disposed between them a short straight bladed rotor or spur gear 56. The blades in p the rotor 56 are equal in number and are in register with the blades in the rotors 54 and 5."). represents a rib which covers only a portion of the peripheries of the rotors and is provided with a fluid inlet 5T wh1ch 1s (lisposed at the center or in line with the rotors 56. Thus the fluid enters the rotors 5G and is forced out in both directions through the t right hand and left hand spiral rotors 54 apd i thereby exerting a pressure in opposite directions from the center and there y bal- -,ancing the end thrust. In Fig. 9 a pair of right hand and left hand spiral rotors are also employed but with two fluid inlets 58 and 59, the fluid exhausting between the inner ends of the rotors.

In Fig. 10 a diagram of a two-stage effect is shown, 60 being the inlet for the first stage of rotors 61 and 62, and 63 the inlet-for tie seoondcstage of rotors 64 and 65. Fluid under its initial pressure may be'forced i through both inlets or ill! exhaust from the l first stage may be utilized to propel the scc ond stage.

ln F g. ll is shown in a diagranunatical manner; a three-stage or triplc-cxpmision effect. 66 and ('7 "represent the first stage of rotors and (38 their inlct: fiil and T0 the second stage of rotors and 71 their inlet; and T2 and T3 the third stage of rotors and T4 1 their inlct. Either the right hand or thc left hand rotor of each stage are conncctcd together and a'cfcrably have one shaft in connnon. The fluid under pressure enters the. first stage at (38, the exhaust from the first stage forms the supply for the second stage and the exhaust from the second stage. the supply for the third stage, as indicated by the arrow runnin through the three stages. In this type of rotary engine the rotors increase in size from the first stage to the third.

- the point of mesh or the bucket formed by,

I-I aving thus described my invention, I will now describe its operation.

Referring to Fig. 5, 76 represents the point of mesh of the blades 77 and 78. Nowsuppose' fluid under ressnre is admitted through the inlet 50, his fluid will iin ingef against the blades 77 and 78, not in a irection at right an les to the blades, but sub-i stantially paral el to them and directlyi toward the point of mesh. This results in! causing the point 76 and the bucket formedi thercat to recedc toward the exhaust end of revolve ii'i op osite directions. The cvcle of a pair of blar. es begins with the first impact of the fluid against them at the moment that i i i the rotors and thus cause the said rotors to% the bucket is formed, and is completed when the same pair of blades reaches the exhaust end of the rotors. The less the spiral angle,;i orthe angle which each blade makes with? the plane through the axis of the rotor, thei greater will be the rate of recession of point of mesh toward the exhaust end of the rotors. As this is equivalent to the bucket? velocity in a turbine, and as the etliciencvof a turbine depends to a large extent, u web 5 the velocity of its lmckets, I am therefore able, by making the spiral angle small, to sea cure. adngh bucket velocity and a rcsultingi high etliciency with alow rotative speed.

In Fig. 3 it will be seen that the port hole 7 4:) exposes several of the blades at the same tune and as one pair of blades starts its cycle before the one or two preceding pairs have finished their cycle. this construction, which is equivalent to a plurality of jets, keeps each workin air of blades under the pressure of the fiui until the point of cutoff is reached. The point of cut-ofi' is reached on a pair of blades when the admission end of said air of blades has assed the outer extremity of the V-shape poi-t hole 45. From the point of cut-off until the time of exhaust the volume of fluid inclosed in said pair of blades expands. The ratio of expansion is determined bv the distance from the extremities of the -shaped port hole to the center line of the rotors, this ratio being made greater as the iort hole is extended. The tlnid of course ias accom- I dished its ctl'ectivc work on any pair of )lndcs when the point of mesh of such pair of blades has reached the ends of the rotors 1 opposite to the inlet, but to reduce leakage l to a minimum. the fluid contained between the blade just tinishing its cycle and the one adjoining it, is carried preferably around between the rotor and the casing 12 for substantially 270 from the point where the i bucket is formed and the cycle commences.

Obviously this invention may be a plied to any use where a prime mover is tesircd am] in thus adnptiiig it to the various uses indicated, modifications may be made which will embody the spirit and essence of the ingvention and some specific details without departing from the invent-ion as herein dislclosed.

a pair of rotors rotatively mounted and each 1 Having thus described my invention, what I claim is: v

1. In a rotary engine the combination of provided with a plurality of spirally disposed and intermeshing tooth blades formed with semi-circular tops, semicircular faces and straight sides connecting said semi-circular to is and said semi-circular faces, said blades orming acute angles with the axes of said rotors.

2. In a rotary engine the combination of a )air of rotors each provided with a pinra ity of spirally disposed and intermcshing tooth b ades, said blades forming acute angles with the axes of said rotors, a rib extending across the inlet side of said rotors parallel to their axes and in conformity to a portion of their peripheries, front and rear heads, bearings carried by said front and rear heads, shafts rigidly secured in said rotors and rotatably mounted in said bearings, the inlet ends of said rotors being in contact with said front head, and means 'more jets of fluid under pressure may be carried by said front head whereby one or made to impinge on said blades.

3. In a rotary engine the combination of a )air of rotors each provided with a plura ity of spirally disposed and intcrineshing tooth blades, said blades forming acute angles with the axes of said rotors, a casin r surrounding said rotors, a rib inte rat witi said casing extending across the inlet side of said rotors, parallel to their axes and in conformity to a ortion of their peripheries, front. and rear lieads fitted to said casing,

bearings carried by said front and rear heads, shafts rigidly secured in said rotors 1 and rotatably mounted in said bearings, the

inlet. ends of said rotors being in contact with said fronthead. and means carried by said front head whereby one or more jets of i fluid under )rcssnro may be made to impingc on Stilt blades.

4. In a rotary engine the combination of a air of rotors each providciLwith a pinra ity of spirally disposed and intermeshing tooth blades, said blades forming acute angles with the axes of said rotors, a casin surrounding said rotors, a rib integral wit l said casing extending across said inlet side of said rotor, parallel to their axes and in conformity to a portion of their peripheries, 2 front and rear heads fitted to said casing,

bearings carried by said front and rear heads, shafts rigidly secured in said rotors and rotatably mounted in said bearings, the inlet ends of said rotors being in contact 1 with said front head, an inlet port in said front head, and one or more jtiH of tlnid I tmilll wa /w surrounding said rotors, a rib integral with} said casing extending across the inlet side} of said rotors, parallel to their axes and in conformity to a portion of their peripheries,

front and rear ends fitted to said casing,-

{ bearings carried by said front and rear f heads, shafts rigidly secured in said rotors and rotatably mounted in said bearings, the;

l inlet ends of said rotors being in eontaett with said front head, an inlet port in said'g front head, a V-shaped aperture eomniuni-t eating with sald'inlet port and disposed int said front head opposite the point of mesh i of said rotors, whereby fluid under pressure may be made to impinge upon said blades.

6. In a rotary engine the combination of a iair of rotors each po vided with a plurality of spirally dis iosed and interineshing toot-h blades, said lades forming acute angles with the axes of said rotors, a easin surrounding said rotors, a rib integral wit i said casing extending across the inlet side of said rotors, parallel to their axes and in conformity to a ortion of their peripheries, front and rear ieads fitted to said casing, bearings carried by said front and rear heads, shafts rigidly secured in said rotors and rotatably mounted in said bearings, the inlet ends of said rotors being in contact with said front head, an inlet port in said front head, an interchangeable ort-hole plate disposed in said front head, usli with the inner face thereof and between said inlet port andtlie said rotors, a V-sheped port through said port-hole plate whereby fluid under pressure may be made to impinge on l said blades.

T. iii a rotary engine the combination of i a pair of rotors each provided with a pliirality of spirally disposed and intermesliing blades forming acute angles with the axes of said rotors, a casing surrounding said rotors, a rib integral with blades, said said casing extending across the inlet side of said rotor, parallel to their axes and in conformity to a ortion of their peripheries, front. and rear ieads fitted to said casing,

bearings carried by said front and rear '5 heads, shafts rigidly secured in said rotors and rotatably mounted in said bearings, the

inlet ends of said rotors being in contact with front. head, an inlet port in said front head, one or more jets of fluid under ressiire leading from said inlet port an impinging upon said blades and regulatin means disposed between said inlet ort and said jet. or jets whereby the speed of the rotors may be governed.

8. In a rotary engine the combination of a pair of rotors each irovided with a plurality of s )irally disposed and intermeshing tooth blatfes, said blades forming acute angles with the axes of said rotors, a casing surrounding said rotors, a rib integral-with said casing extending across the inlet side of said rotors, 1 parallel to their axes and in conformity to a iportion of their peripheries, front and rear 3 ieads fitted to said casing, bearings carried lby said front and rear heads, shafts rigidly secured in said rotors and rotatably mounted in said bearings, the inlet ends of said rotors being in contact with said front head, thrust bearings disposed in said rear head, an inlet port in said front head, an interchangeable port-hole plate disposed in said front head, flush with the inner face thereof and be- -tween said inlet port and the said rotors, a V-sha ed port through said port-hole plate where )y fluid under pressure may be made to im inge on said blades.

9. n a rotary engine the combination of a pair of rotors each rovidedwith a plurality of spirally dispose and intermeshing tooth blades, said blades forming acute angles with llllt. axes of said rotors, a casing surrounding said rotors, a rib integral with said casting extending across the inlet side of said rotors, paral el to their axes and in con- ;formity to a portion of their peripheries, ifront and rcar'heads fitted to saidcasing, ibearings carried by said front and rear ilieads, shafts rigidly secured in said rotors and rotatably mounted in said bearings, the

ginlet ends of said rotors being in contact with said front head, an inlet port in said ifront head, an interchangeable ort-hole plate disposed in said front head, ush with I port and said rotors. a V-sliaped through said port-hole plate. a slide disposed fare of h'tlltlPOl'l-llfllt plate and means conn tooth blades, said blades forming acute angles with the axes of said rotors, a casing surrounding said rotors and having its inner wall in conformity with the periphery of each said rotor for substantially 1270, startmg froin the point of mesh of said blades tlll tl extending around from the inlet side of sa d rotors, an exhaust port in the side. of said casing opposite the inlet. side of said rotors, front and rear heads fitted to said casing, bcarings'carried by said heads, shafts rigid y secured in said rotors and rotatably mounted in said bearings. the inlet. end of said rotors being in contact with said front 3 the inner face thereof and between said inletv port.

in said front head andslidable on the inner neeting with said slide whereby tluid under V l l a mir of rotors eac head, an inlet port in said front head and one or more jets of fluid under pressure leading from said port and impinging upon said blades. 11. In a rotary en ine the combination of E provided with a phi-l ra ity of spirally, disposed and intermeshingi tooth blades, said blades forming acute angles with the axes of said rotors,'a casing": surrounding said rotors and having its in-i ner wall in conformity with the periphery of each said rotor for substantially 270,i starting from the point of mesh of saidi blades and extending around from the inletl side of said rotors, an exhaust port in thei side of said casing opposite the inlet sidei of said rotors, front and rear'heads fitted; to said casing, bearings carried by said heads, shafts rigidly secured in said rotors. and rotatably mounted in said bearings, the inlet end of said rotors being in contact with a said front head, an inlet port in said front; head, a V-shaped aperture communicatin with said inlet portand disposed in said front head op )osite the point of mesh of said rotors, whereby fluid under gressure may be made to impinge u )on said b ades.

12. In a rotary engine the combination of two or more )flllS of rotors each provided. with a -llural ity of s irally disposed and intermes ting tooth blat es, said blades formt ing acute angles with the axes of said rotors, casings surrounding said rotors, a rib integral with said casings extending across the inlet side of said rotors parallel to their axes and i in conformity to a portion of their periph- Y cries, front and rear heads fitted to said casing or casings. bea rings carried by said front. and rear heads, shafts rigidly secured in said rotors and rotatably mounted in said beariugs, one or both 0 said rotors of each pair having a shaft in common, the inlet ends of WWI! pair or pairs of rotors being in contat-t with said front head or heads, and means carried by said front head or heads 1 whereby one or more jets of fluid under pros-sure may be made to impinge on the said blades of each pair of rotors..

iii. In a rotary engine the combination of two or more pairs of rotors each rovided with a plurality of spirally disposet and in lei-meshing tooth blades said blades forming acute angles with the axes of said rotors, casingssurrounding said rotors, a rib intc ral with said casings extending across the inlet sideof said rotors parallel to their axes and in conformity to a portion of their peripheries, front and rear heads fitted to said casings, bearings carried by said front a and rear heads, shafts rigidly secured in said rotors and rotatably mounted in said bcarings, one or both of said rotors of each pair ha ring a shaft in common, the inlet ends of each pair or pairs of rotors being in contact with said front head or heads, an inlet port in each said front head, and one or more jets of fluid under pressure leading from said ort or iorts, and impinging upon the said lades of each pair of rotors.

14. In a rotary engine the combination of two or more pairs of rotors each provided with a lura ty of spirally disposed and intermes ring tooth blades said blades forming acute angles with the axes of said rotors,

casings surrounding said rotors, a rib interal with said casings extending across the inlet side of said rotors parallel to their axes land in conformity to a portion of their peripheries, front and rear heads fitted to said casings, bearings carried by said front and rear heads, shafts rigidly secured in said rotors and rotatably mounted in said bearings one or both of said rotors of each pair havin a shaft in common, the inlet E ends of cum pair or pairs of rotors being in l contact with said front head or heads. an inlet port in each said front head, a V-shaped aperture communicating with said '2 inlet port and'disposed in each said front head op )osite the mint of mesh of said rotors, w hereby fluid under pressure may be made to impinge upon the said blades of each pair of rotors.

15. A rotary engine comprising a )air of rotors rotatively mounted and cam pro vided with a luralitv of spirally disposed and intermcshm tooth blades, the faces and top of each sai tooth blade formin substantially a semi-circle, the flanks 0 each said tooth blade being formed in substantially the arcs of a circle so that the two flanks of adjoinin tooth blades form substantially a. semi-circle and the sides of said tooth blades at. or near the pitch line, where the faces and flanks join, being formed substantially straight for a short distance.

16. In a rotary engine the muubination of two or more mirs of rotors each provided with a lura ity of spirally disposed and intertnes ting tooth blades said blades forming acute angles with the axes of said rotors, casings surrounding said rotors. a rib integral with said casings extending across the inlet side of said rotors parallel to their axes and in conformity to a portion of their peripheries, front and rear heads fitted to said casings, bearings carried by said front. ,and rear heads, shafts rigidly secured in said rotors and rotatably mounted in said bearings, one or both of said rotors of each pair having a shaft in common, the inlet ';ends of each pair or pairs of rotors being -in contact with said front head or heads. an inlet port in each said front head, an interchangeable ort-hole )late dis inset] in each said front lead, flush with tie inner 1 face thereof and between said inlet port and the said rotors, a V-shaped port. through 3 each said port-hole plate whereby fluid under pressure may be made to impinge on the said blade of each pair of rotors. 17. In a rotary engine the combination of two or more pairs of rotors each rovided with a plurality of spirally disposer and intermeshing tooth blades, said blades form-, ing acute angles with the axes of said rotors, g casings surrounding said rotors, a rib interal with said casings extending across the i inlet side of said rotors parallel to their axes i and in conformity to a portion of their peripheries, front and rear heads fitted to said casin s, bearings carried by said front and l rear leads, shafts rigidly secured in saidt rotors and rotatably mounted in said beari ings one or both of said rotors of each pair 5 having a shaft in common. the inlet ends of each pair or pairs of rotors being in contact with said front head or heads, an inlet v port in each said front head, one or more jets of fluid under pressure leading from each said inlet port and impinging upon the said blades of each pair and regulating means disposed'between said inlet port and said jet or jets, whereby the speed of the rotors may be governed.

18. In a rotary engine the combination of two or more pairs of rotors each rovided with a plurality of spirally dis ose and intermeshing tooth blades said lades forming acute angles with the axes of said rotors, casings surrounding said rotors, a rib integral with said casings extending across 1 the inlet side of said rotors parallel to their axes and in conformity to a portion of their peripheries, front and rear heads fitted to said casings, bearings carried by said front and rear heads, shafts rigidly secured in saulu'otors and rotatably moiinted in said hcarmgs, ono or both of said rotors of each pair having a shaft in common, the inlet i f each pair or pairs of rotors bein in 1 contact with said H thrust bearings disposed in each said rear 1 head, an inlet port in each said front head, an interchangeable port-hole plate disposed in each said front head, flush with the inner t face thereof and between said inlet port and the said rotors, a V-shaped port through s each said port-hole plate whereby fluid unl der pressure may be made to impinge on the I said blade of each pair of rotors. 19. In a rotary engine the combination of two or more pairs of rotors each rovided with a plurality of spirally disposer and intermeshing tooth blades, said blades forming acute angles with the axes of said rotors. casings surrounding said rotor's, a rib integral with said casings extending across the inlet side of said rotors parallel to their I axes andm conformity to a portion of their pv tlpllel ltfi, front and rear heads fitted to said casings, bearings carried by said front and rear heads, shafts rigidly secnrod i front head or heads, 5

",said rotors and rotatably mounted in said lbearings, one or both of said rotors of each ,pair having a shaft in common, the inlet ends of one 1 pair or pairs of rotors being in ,contact with said front head or heads, an inlet port in each said front head, an interchangeablc ort-hole plate disposed in each isaid front end, flush with the inner face thereof and between said inlet port and each pair of rotors, a V-shaped port through each saidport-hole plate, a slide dis )osed in one or more of said front heads tan slidable on the inner face of one or imore of said port-hole plates. and means connecting wit 1 said slide or slidcs whereiby fluid under pressure may impinge upon the said blades of each pair of rotors and l the amount of fluid passing through said V- shaped port-holes may be regulated and the 5 speed of the rotors governed.

20. In a rotary engine the combination of two or more pairs of rotors each rovided with a plurality of spirally disposcd and intermeshing tooth blades. said blades forming acutc angles with the axes of said rotors, casings surrounding said rotors and having their inner walls in conformity with the periphery of each said rotor'tor substantially 270, starting from the point of mesh of said blades and extending around a from the inlet side of said rotors, an exl haust rt in the side ofeach said casing 1 opposi e the inlet side of said rotors, front and rear heads fitted to each said casing, hearings carried by said heads, shafts rigidly secured in said rotors and rotatabl mounted in said bearings, one or both rotors of each pair having a shaft in common, the inlet. end of each pair of said rotors being in contact. with each said front head. an inlet port in each said front head, and one or more jets of fluid under pressure leadin; from each said port impinging upon said blades.

21. In a rotary engine the combination of two or more pairs of rotors each )rovidcd with a plurality of spirally disposed and intermeshing tooth blades, said blades fornr ing acute angles with the axes of said rotors, casings surroundin said rotors and T having their inner walls in conformity with the periphery, of each said rotor for substantially 270, starting from the point of mesh of said blades and extending around from the inlet side of said rotors, an exhaust port in the side of each said casing opposite the inlet side of said rotors, front and rear heads fitted to each said casing. bearings carried by said heads, shafts rigidly secured in said rotors and rotatably mounted in said bearings, one or both rotors of each pair having a shaft. in common. the inlet end of each pair of said rotors be ihg in contact with each said front head, an inlet port in each said front. head, a V shaped aperture communicating with said I disposed and intermeshing tooth I said blades forming acute angles with thei inlet port and disposed in each saidfront head opposite the inlet port and disposed in each said front head opposite the point of mesh of said rotors, whereby fluid under pressure may be made to impinge upon the said blades of each pair of rotors. l 22. In a rotary engine the combination of l two or more pairs of rotors, each pair greater l in diameter than the one preceding it, each rotor provided with a plurality of s irally lilades.

axes of said rotors, casings surrounding said i rotors, a rib integral with said casings extending across the inlet side of said rotors, i 1

parallel to their axes and in conformity to a portion of their )eripheries, front and rear 5 ends fitted to said casings, bearin s carried 3 by said front and rear heads, sha ts rigidly secured in said rotors and rotatably mounted in said bearings, one rotor of each pair on the same side of the engine having one shaft in common. fluid inlet means car ied by the said front head of the smallest air of rotors and means carried by the said front heads and rear heads of the casin surrounding the other pairs of rotors, w iereb the exhaust fluid from the first pair is ma e to impinge on the blades of the next pair 1 and a multistage effect produced.

a o a n 28. A, rotary engine comprising a pair of 1 rotatirely mounted and each rovided with a plurality of spirally dis oset and intermeshiug tooth blades, the aces and top of each of said tooth blades forming substantially a semi-circle, the flanks of each tooth blade being formed in substantially the arcs of a circle so that the two flanks of adjoining tooth blades form substantially a semi-circle and the said tooth blades being of such proportions relative to the diameters of said rotors that the length of the line of contact of the. intermeshing teeth will be substantially equivalent to t. to entire perimeter of one of said tooth blades.

24. In a rotary engine the combination of g a pair of rotors each provided with a pluralj ity' of spirally disposed and intermeshin tooth blades, rotor shafts, bearings in whic said rotor shafts may be mounted, a rib, a front head in contact with the outer ends of said rotors, and a port so placed with reference to said rotors that admission of the motive fluid into any tooth bucket is substantially discontin ued before said tooth bucket has developed its full volume, thereby allowing the contained fluid to expand from this point to the point where the said tooth bucketdevelops the full volume.

.25. In a rotary engine the combination of a pair of rotors eacli provided with a plura ity of spirally disposed and intermeshing tooth blat es, a casing surroundin said r0- tors. a rib which covers only a portion of the peripheries of said rotors andavhich s provided with a fluid inlet sa d inlet being so placed with reference to said rotors that admission of the motive fluid into the tooth ibucket is substantially discontinued before i said tooth bucket has developed its full vol- 5 ume, rotor shafts and bearings in which sa d rotor shafts may be mounted, one of sa d I shafts being rigidly secured in one of said I rotors.

26. A rotary engine comprlsin a pair of i rotors rotatably'mounted and eac 1 provided i with a plurality of spirallly disposed and intermeshing tooth blades, t e faces and-top of leach of said tooth blades forming substanitially a semi-circle, the flanks of each tooth lblade being formed in substantially the arcs of a circle so that the two flanks of ad oiniing tooth blades form substantially a semicircle and the said tooth blades being of such proportion relative to the diameters of said I rotors teeth will be substantially a line contact at an instant. a testimony whereof I have hereunto set imy hand in the presence of two witnesses.

JOHN HERBERT VAN DEVENTER.

, Witnesses: t Erma. A. Ksnnr, J. WM. ELLIS.

that the contact of the intermeshing 

